Can someone check this?

Question

Hi Everyone,
I'm just wondering if these two classes Movie and Viewer and the Application class look right for what I've done so far for the following problem. Any comments are greatly appreciated.
Also, using if statements, how am I going to check if the user is actually permitted to see the film and in what class will I put it in?
Using a class to represent each of the major entities involved and an application class which controls object and user interaction.
Write a program which implements a cinema entry system, according to the following rules:
Anyone can go to see a U rated film.
Only those aged 12 or over, or accompanied by an adult can go to see a PG rated film.
Only those aged 12 or over can go to see a 12s rated film.
Only those aged 15 or over can go to see a 15s rated film.
Only those aged 18 or over can go to see an 18s rated film.
Your program should present the user with the following list of film options:
(a) Blair Witch Project, 18s
(b) American Pie, 15s
(c) Lord of the Rings, 12s
(d) It?s a Wonderful Life, PG
(e) Aladdin, U
The program should ask the user what film they want to see, and then determine whether or not they are permitted to see the film. If they are not permitted, then
a list of the films they can see will be displayed.
Thanks,
A novice Java programmer
public class Movie
private final int EIGHTEEN = "18";
private final int FIFTEEN = "15";
private final int TWELVE = "12";
private final String PG = "PG";
private final String U = "U";
private String title; //title of the movie
private String rating; //rating of the movie
private Boolean isAcompaniedByAdult; //if viewer is accompanied by an adult
public Movie (String t, String r)
title = t;
rating = r;
//Method to get the title of the movie
public String getTitle()
return title;
//Method to set the title of the movie
public void setTiltle(String t)
title = t;
//Method to get the rating of the movie
public String getRating()
return rating;
//Method to set the rating of the movie
public void setRating(String r)
rating = r;
public class Viewer
//age of the viewer
private int age;
private boolean isWithAdult;
public Viewer (int a, boolean w)
age = a;
isWithAdult = w;
//Method to get the age of the viewer
public int getAge()
return age;
//Method to set the age of the viewer
public void setAge(int a)
age = a;
//Method for if the viewer is with an adult
public boolean isWithAdult(Viewer v1)
if (isWithAdult(v1))
     return true;
else
     return false;
public class CinemaApp
public static void main(String [] args)
int Movie;
int Age;
Boolean isWithAdult;
System.out.println();
System.out.println("Welcome to the Cinema Entry Program");
System.out.println();
System.out.println("Movies Currently Available to View:");
System.out.println("1. Blair Witch Project, 18s");
System.out.println("2. American Pie, 15s");
System.out.println("3. Lord of the Rings, 12s");
System.out.println("4. It's a Wonderful Life, PG");
System.out.println("5. Aladdin, U");
System.out.println();
do
     Movie = Input.readInt("Please enter the number which corresponds to the movie you wish to view: ");
while ((Movie<1) || (Movie>12));
if (Movie == 1)
     Movie m1 = new Movie("Blair Witch Project","18s");
else if (Movie == 2)
     Movie m1 = new Movie("American Pie","15s");
else if (Movie == 3)
     Movie m1 = new Movie("Lord of the Rings","12s");
else if (Movie == 4)
     Movie m1 = new Movie("It's a Wonderful Life","PG");
else if (Movie == 5)
     Movie m1 = new Movie("Aladdin","U");
Viewer v1 = new Viewer(Input.readInt("Please enter your age: "), Input.readBoolean("Are you acompanied by an adult? (y/n): "));

Answer 1

There are a few things I don't quite understand. I'd love to explain!
Why would you declare and initialise the ratings in the
movie class if your using them in the viewer class.First, a little clarification: those ratings are static final variables. This means that, no matter how many instances of Movie you make, there is only one set of those ratings. If you've ever used enumerations in C++, it's a way of simulating those. In effect, it makes the logic easier and more efficient. Basically, NEVER refer to a rating by it's int value (don't use "1" instead of "RATED_U"). Anytime you want to refer to the rating 15s, always use Movie.RATED_18S.
Why did I put them in the Movie class? Because the rating is a property of a Movie, not a Viewer. Thus, the rating should be kept in the Movie class.
Basically, look at my suggestions as a lesson in some principles of Object Oriented design. You don't want to make the rating a String, because of the following case:
Using this as the variable declaration for the ratings:
private final String U = "U";
//etc...What if someone tried to assign "R" as the rating for a movie? They would be able to, because there are no control structures on what a String can be. If you use static final variables, however, they're given a set list of values they can assign as a rating.
This methodology is used commonly in the Java APIs (for example, MimeMessage.RecipientType.TO). It's a good practice, and in this program, it would simplify the logic greatly.
Secondly, I don't understand this if(this.getAge()
= 12 || this.isWithAdult()), what is gt?
"this" refers to the current instance of the class. It's not actually necessary in this context. You could just as easily replace those lines with if(getAge() >=12 || isWithAdult())
ThanksAnytime! This stuff I've thrown at you isn't exactly basic programming... if it's still unclear, feel free to ask more questions.